Audio Database


Exclusive C7
1,200,000yen(around the 1991 time)

L which supplies without a stain the technology which it can have in quest of a true stereophonic, and can also be said to be the origin of a stereophonic
The highest-class stereo preamplifier which aimed at the "stereo transmit error zero" which reproduce the sound from R as a homogeneous thing.

The mono-construction structure where it became independent completely is adopted from a power cord to the input/output terminal of a rear surface panel.
furthermore, right and left -- the thorough analysis of the magnetic field in the set which has on a homogeneous play, a temperature, the oscillation, etc. is conducted making full use of the newest instrumentation equipment, all the parts including adoption of a newly developed part are considered as a right-and-left independent symmetrical type layout, and homogeneous-ization of the transmit is attained.
Moreover, various consideration is carried out in order to attain stereo transmits error zero, such as adoption of simple-izing of a signal path, and the remote control system in a set.

The magnetism generated from a power transformer or a smoothing capacitor also affects a propagation circuit, generates an induction noise, and degrades a tone quality. Paying attention to this influence, equalization of the measure against a magnetic shield of main component partses, such as a power transformer of low flux density and a development of the capacitor which cancels a magnetism, and the magnetic distribution in a set is attained.

The newly developed low flux density transformer and the capacitor (complimentary capacitor pair) of ± pair which negates a mutual magnetism are adopted.
Furthermore, vibration proof and the measures against a vibration suppression, such as an aluminum die-casting chassis which realized floating-izing of a printed-circuit board and absent-resonance-ization, are taken.
Moreover, in order to correspond also to deformation by the heat of a chassis, the influence on the tone quality by mechanical members, such as a layout of each part in consideration of the influence of adoption of the chassis which calculated stress, heat deformation, etc., is solved, and it corresponds.

In consideration of the property of a conductor that a transition of a temperature turns into a transition of a resistance value affecting a tone quality, a control of a heat dissipation is begun, according to the suitable layout of the part used as a heat source, the inside of a set is made into a temperature environment like a thermostatic oven, and homogeneous-ization of a sound on either side is attained.

In order that right and left may secure the independence of the perfect mono-construction which became independent completely, the volume and the function switch also adopted the remote control in a set, and the clear separation on either side is realized.

Circuitry has one-channel 2 amplifier 2 buffer amplifier composition.
In order to drive an input to the volume and Rec output of a generous high-impedance by a low-impedance,Installing [ and also ] buffer amplifier between the input selector, between volumes and a volume, and the phase switchpoint, two flat amplifier has adopted the amplifying circuit by aluminum high Brit IC.

In order that a power-source part may become independent to three transformers for right and left and a control and may eliminate the influence on a tone quality, the power transformer which operates with low flux density is developed newly and used for it. Moreover, the occurrence of the noise is suppressed by setting up operate on the good point of a linearity.
Furthermore, a smoothing capacitor develops newly the complimentary capacitor pair where each magnetic field cancels mutually and which it suits paying attention to the magnetic field which is a positive and negative side and is generated, and is suppressing the influence which a magnetic field has on a tone quality.

In order to eliminate a noise thoroughly and to secure the purity of the signal from the source, the input circuit has adopted the separate grounding circuitry which turns on and off simultaneously not only the hot side but the grounding side. This flows in from an earth line, and also the noise from an equipment is cut.

Aluminum with the outstanding thermal conductivity and a shielding property is used for the substrate of the hybrid IC adopted as the amplification part of flat amplifier. The influence of the tone quality on the heat which causes a tone-quality failure by this, or a magnetism is put into practice and suppressed.

The printed-circuit board which is easy to be influenced by oscillation was floating-ized from the holder by the dumping material of the special rubber vibration insulator, and the influence of the tone quality on an oscillation is cut.

In order to obtain the independence of each channel, and symmetric property on either side, the remote control system in a set was adopted as the change of a volume and a function, and reservation of an independence on either side is realized.
If the control unit of the front panel is operated manually, the volume and function circuit changing switch which have been arranged at the set rear will operate by drive of a motor, and will be set to the position of hope.
Moreover, when not operating it, the generator for motor drives is set to being turned off, and the influence on a tone quality is cut.

In order to reproduce the outstanding tone quality, he is examining each of component partses carefully, and the oxygen-free-high-conductivity-copper shielding wire of 99.99% of a purity is used for signal path product-line material.

In order to supply energy to each of three transformers direct, the oxygen-free-high-conductivity-copper quality very-thick power cord of six cores is adopted.
It also insulates doubly and using carbon for the color pigment of an insulating material moreover etc. also supports the influence on the tone quality by a pigment.

Internal Layout
Power-source part

Rating of a mode
Form Stereo preamplifier
Input sensitivity/impedance Phono man month: 2.5mV / 50kohm
compact disk, Tuner, Line1, 2, 3, 4 and 5, Tape play1, Tape2:150mV/50kohm
Balance in 1, 2:150mV/600 ohm
An Output voltage/impedance Tape rec1, 2:150mV / 1kohm
Output1:1V/0.1 ohm
Output2(Balance): 1V/200 ohm
Maximum output level
(0.01% of a distortion, 20Hz - 20kHz)
Tape rec1 and more than 2:12V (at the time of Phono)
Line4 and more than 5 out:12V (at the time of Phono)
More than Output1:5V / 600ohm
Output2(Balance): More than 3V / 600ohm. More than 5V/10kohm
Phono maximum permissible input Phono man month: 200mV or more (1kHz, 0.01% of distortion)
SN ratio Phono MM:87dB
Supply voltage AC100V, 50Hz/60Hz
Power consumption 70W (Electrical Appliance and Material Control Law)
Dimensions Width 460x height 158x depth of 446mm
Weight 27.5kg